(a) Field of the Invention
The present invention relates to a wrench tool, more particularly to an improved adjusting structure for a ratchet wrench.
(b) Description of the Prior Art
Referring to FIGS. 1 and 2, a conventional ratchet wrench essentially includes a chamber with an open bottom provided at a working end at a head portion of the wrench. One end of the chamber is provided with a ratchet wheel. The center of the ratchet wheel is connected to a drive rod. The center of the drive rod is provided with a movable type insert control member that controls the drive rod to stably couple with a workpiece or another fitting member. The insert control member is controlled via a push button extending out of the drive rod and a top face of the chamber. The other end of the chamber is provided with two curved grooves in a wall surface thereof for limiting base portions of two trigger blocks. Open ends of the two trigger blocks have teeth that are engageable with peripheral teeth of the ratchet wheel. An eccentric push rod is disposed between the two trigger blocks. The push rod is controlled via a trigger rod provided at a top face of the wrench. Two side walls of the chamber are respectively provided with springs urging against the trigger blocks.
The trigger rod is manipulated to cause the push rod to push away one of the trigger blocks so that the push block compresses the corresponding spring, and the teeth of the trigger block disengage from the ratchet wheel. On the contrary, the other trigger block or the urging action of the other spring causes the teeth to engage with the ratchet wheel. Thus, operation of the wrench can produce a predetermined operating direction, or conversely, the wrench is in idle rotation to return to its original position.
The above-described conventional ratchet wrench has the following disadvantages:
1. The torque of the wrench is small. The number of teeth that can be provided at the end portion of the elongated trigger block is limited. Insufficient number of engageable teeth between the ratchet wheel and the trigger block results in small torque of the wrench, which may cause wear or damage of the teeth during operation. Besides, engagement is not assured, which may affect operation of the wrench.
2. A large number of components make assembly inconvenient and time-consuming. During assembly, the two trigger blocks have to be disposed first. Then, the eccentric push rod is assembled, and it has to be noted that rotation of the push rod can push away one of the trigger blocks. Next, the push rod and the push rod are coupled. Subsequently, two springs are fitted between the two trigger blocks and the two side walls. Assembly is very completed and time-consuming.
3. Positioning of the components is not secure. The springs are simply mounted by fitting without any positioning means and may easily become disengaged. The base portions of the two trigger blocks are only limited in the two curved grooves and may disengage in the direction of the ratchet teeth. These problems seriously affect the operation and durability of the wrench.
The main object of the present invention is to provide an improved adjusting structure for a ratchet wrench, in which the wrench can bring a workpiece to rotate in an action direction or to perform idle rotation in a reverse direction back to its original position. In addition, the present invention can be quickly assembled and positioned, and the torque of the wrench can be increased. Furthermore, the wrench can drive the workpiece with a stable and uniform force, thereby enhancing operability and durability of the wrench.
In order to achieve the aforementioned object, the improved adjusting structure according to the present invention is adapted for use in a tool handle. One end of the tool handle is provided with an open chamber sealed by a seal piece. The chamber is provided with a trigger structure including: a ratchet wheel disposed at an end portion of the chamber; a positioning groove provided in a wall of another end portion of the chamber; a trigger block having a circular block-shaped base portion and a toothed block expanding radially outward from the base portion, the base portion being disposed in the positioning groove, the base portion of the trigger block being centrally provided with a polygonal hole; a trigger structure including a disk portion, one side of the disk portion being provided with a shaft that is provided with a polygonal block, the shaft extending into the trigger block, the polygonal block fitting into the polygonal hole; a positioning assisting structure including at least one through hole formed in the toothed block of the trigger block, the through hole having a spring fitted therein. The spring has two ends, each of which is provided with a positioning ball. The positioning ball has an end portion provided with a positioning rod extending through and being retained in the spring. The wall surface of the chamber and the seal piece are respectively provided with hemispherical recesses at positions corresponding to positions adjacent to the positioning balls such that when the trigger block is actuated by the trigger structure to slant and the toothed face on one side engages the ratchet wheel, the peripheral surfaces of the two positioning balls can engage the hemispherical recesses on the same side.